This invention relates to a nonocclusive drug delivery device and to a method for its manufacture.
One known type of transdermal drug delivery device, also variously referred to as a medical bandage, treatment pad, drug patch, etc., includes a drug depot, or reservoir, in the form of a drug-storing matrix or carrier and an adhesive for attaching or securing the device to a surface of unbroken skin.
In one particular type of construction, a known drug delivery device is provided as a laminate of a thermoplastic microcellular foam layer carrying a measured quantity of drug or drug-containing composition, the upper surface of the foam layer being bonded to a thermoplastic film barrier layer and its lower surface possessing a contact adhesive. It has been found that a drug delivery device of this general construction may be liable to one or more drawbacks which preclude its effective use and practical acceptance. For example, unless the peel strength of the device is significantly less than the strength of the bond between the foam and barrier layers, on peeling the device from the skin, separation (i.e, delamination) of the foam and barrier layers may occur with portions of foam continuing to adhere to the skin. Another problem can arise when, due to the physicochemical nature of the foam and the drug or drug-containing composition, the latter migrates into the adhesive thereby impairing the strength of the bond by which the device is held to the skin.